Swift UIKit label text doesn't update / view doesn't update - ios

Question

I have a problem:
I have a list of items this is controller A, and when I click on any item I go to controller B (item info), I then execute the ledLightingButton_Tapped function by pressing the corresponding button that activates the LED indicator for the animal.
#IBAction func ledLightingButton_Tapped(_ sender: Any) {
if !GlobalData.shared.led_animals.contains(GlobalData.shared.selectedAnimalId) {
GlobalData.shared.led_animals.append(GlobalData.shared.selectedAnimalId)
}
activateLED(at: GlobalData.shared.selectedAnimalId)
}
func activateLED(at animalId: String) {
ServerSocket.shared?.perform(
op: "ActivateLED",
with: [
"light_duration": "180",
"led_color": "White",
"client_data": "",
"led_animals": [animalId]
]
) { err, data in
guard err == nil else { return }
print(data)
let ledStatus = data[0]["led_request_status"].stringValue
self.ledStatusLabel.text = ledStatus
GlobalData.shared.isActiveLED = true
self.startTimer()
}
}
Upon successful activation, the animal number is added to the array, and the startTimer is called which every 10 seconds requests checkLEDStatus for all animals in the array.
func startTimer() {
timer = Timer.scheduledTimer(timeInterval: 10.0, target: self, selector: #selector(updateCowStatus), userInfo: nil, repeats: true)
}
#objc func updateCowStatus() {
self.checkLEDStatus()
}
func checkLEDStatus() {
ServerSocket.shared?.perform(
op: "CheckStatusLED",
with: [
"light_duration": "180",
"led_color": "White",
"client_data": "",
"led_animals": GlobalData.shared.led_animals
]
) { err, data in
guard err == nil else {
GlobalData.shared.isActiveLED = false
self.stopTimer()
return
}
DispatchQueue.global(qos: .background).async {
for i in 0..<data.count {
if GlobalData.shared.selectedAnimalId == data[i]["animal_id"].stringValue {
let ledStatus = data[i]["led_request_status"].stringValue
if ledStatus.contains("Fail") {
guard let index = GlobalData.shared.led_animals.firstIndex(of: GlobalData.shared.selectedAnimalId) else { return }
GlobalData.shared.led_animals.remove(at: index)
}
DispatchQueue.main.async {
self.ledStatusLabel.text = ledStatus
}
}
}
}
}
}
The current status of the animal is displayed on the label. If you go in the controller A and activate the status + get a result from checkedLEDstatus - it is work for one animal - everything works, but if you go to controller B, activate for animal number 1, go out and open animal number 2 - perform activation, return to animal number 1 - then the label is no longer is updated, it does not display the new value, but I check it from debugging and property self.ledStatuslabel.text contains new value but UI didn't update. self.ledStatuslabel.text show old value.
Please help me, thanks!